Just to close this out. The car has arrived safely with no damage and nothing missing from inside the car. I did put the car in valet mode so nobody could get into the cargo area. This helped by the cargo barrier.
It was 8 days from dropping it at the depot in Darwin to it being delivered to my front door in Southern Sydney.
Interestingly I got to talk to the truck driver in Darwin. A really good guy who took an interest in looking after the car. He asked about dropping the air suspension down so he could make sure he didn't exceed the maximum height that a truck is allowed to be.
I used SMB transport and the cost was $1400 which I think is very reasonable given the distance.

